Apparatus for introducing a drop-in thermocouple into a basic oxygen furnace

ABSTRACT

An apparatus for introducing a drop-in thermocouple into a molten ferrous bath in a basic oxygen furnace, said apparatus includes a combination closed-compartmentized holding box and charging chute. Each compartment of the box is provided with a restraining means, anchoring means, means for introducing a coolant gas therein and means for electrically connecting the thermocouple cable to an outside recording device. The charging chute includes a wide holding portion whose sides converge to form a restricted funnellike charging portion by which the thermocouple is guided downwardly into the furnace.

O United States Patent 1 1 3,597,975

[72] inventors David W. Kern [56] RelerencesCited Sllttdlle; UNITEDSTATES PATENTS 2| A I N s' 'ff g' 3,390,578 7/1968 Moore 73/359 fg. 116968 3,396,580 8/l968 Cole 7s/3s9x (45] Patented Aug. 10, 1971 PrimaryExaminer-Stanley H. Tollberg [73] Asaignee Bethlehem Steel CorporationAttorney-Joseph J. OKeefe [541 APPARATUS FOR INTRODUCING A DROP-INTHERMOCOUPLE INTO A BASIC OXYGEN FURNACE 3 Claims. 5 Drawing Figs. [52][1.8. CI. 73/343, 73/359 [51] Int. Cl. 601k 1/08 [50] Field at Search73/34] ABSTRACT: An apparatus for introducing a drop-in thermocoupleinto a molten ferrous bath in a basic oxygen furnace, said apparatusincludes a combination closed-compartmentized holding box and chargingchute. Each compartment of the box is provided with a restraining means,anchoring means, means for introducing a coolant gas therein and meansfor electrically connecting the thermocouple cable to an outsiderecording device. The charging chute includes a wide holding portionwhose sides converge to form a restricted fun-- nellike charging portionby which the thermocouple is guided downwardly into the furnace.

Patented Aug. 10, 1971 INVENTORS M Kern Q. Sfe/fs APPARATUS FORINTRODUCING A DROP-IN THERMOCOUPLE INTO A BASIC OXYGEN FURNACE IBACKGROUND OF THE INVENTION 7 In the refining of molten iron and scrapinto steel by the basic oxygen process, it is necessary for the operatorto know the temperature of the molten bath near the end of the refiningperiod. Apparatus has been developed whereby an immersion-typethermocouple may be lowered into the molten bath or by which athermocouple may be dropped from a height into the molten bath. However,charging of a drop-in thermocouple is extremely hazardous because of thehostile environment from which it must be charged. The hot and dustyhostile environment makes it extremely difficult to charge thethermocouples by present-day apparatus.

It is therefore the object of this invention to provide apparatus forcharging a drop-in thermocouple into a basic oxygen furnace which issafe and reliable.

SUMMARY OF THE INVENTION Broadly, the apparatus of the inventionincludes a combination closed compartmentalized holding box and aninclined charging chute. Each compartment of the box contains arestraining means to prevent premature entry of a drop-in thermocoupleinto a basic oxygen furnace, an anchoring means, means for electricallyconnecting a thermocouple cable to a recording device and means forallowing the entrance of cooling gas into the compartments of the box.The closed inclined chute has a holding portion and a downwardlydirected funnellike charging portion whereby a drop-in thermocouple maybe guided into the furnace.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional viewshowing the relationship between a basic oxygen furnace and theapparatus of the invention with a drop-in thermocouple in the moltenferrous bath in the furnace.

FIG.'2 is a view in sectional elevation of the apparatus of theinvention.

FIG. 3 is a top view of the inclined chute portion of the apparatus.

FIG. 4 is a sectional view on the line 4-4 of FIG. 3 showing one of thedividing ribs in the box.

FIG. 5 shows another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,FIG. 1 shows a drop-in thermocouple 11 in a molten ferrous bath 12having a slag cover 13 thereon in a basic oxygen furnace 14 after it hasbeen released from the apparatus of the invention. The ap' paratus 10includes a combination closed compartmentalized holding box 15 in whicha plurality of drop-in thermocouple assemblies 11a are placed, and adownwardly extending inclined chute 16. A drop-in thermocouple assemblycomprises the thermocouple 11, a packing tube 11d and a multiple wirecable 11b. The apparatus 10 is supported by any suitable means 100, forexample, a metal superstructure on the service floor 10b of the basicoxygen furnace shop. Multiple wire cable 11b connects the thermocoupleto an outside recording device 11c. The inclined chute 16 extendsdownwardly to the lance opening 140 in the exhaust hood 14b throughwhich an oxygen lance 14c is lowered into the furnace 14.

The apparatus of the invention is shown in detail in FIG. 2.

The apparatus is basically a combined closed compartmentalized box 15generally rectangular in cross section having a forward portion 15c anda rear portion 15d and a charging chute 16 extending forwardly anddownwardly from 150.

The closed compartmentalized box 15 has twoverticalparallel-longitudinal sidewalls lSa, a base 17, a cover 18parallel to the base 17 and a rear wall 19. The cover I8 is pivotallyattached by suitable means, for example, a piano which extends thelength of the rib 20. An anchor post 22 is provided in the rear portion15d of the box 15 around which the cable 11b may be cinched. Extendingoutwardly from the rear. wall 19 of the box 15 is a bracket 23 to whicha first binding post 24 is attached. The wires in the cable 11b areattached to the binding post 24. Extending through the lower portion ofthe rear wall 19 is a gas intake 25 aligned with a gas passage 26 formedby the supporting legs 20a and 20b of the interior vertical rib 20. Inthe forward portion of the box 15 is a second binding post 27 which maybe attached to the upper portion of the sidewall 15a or the vertical rib20. Extending therefrom are two metallic wires 28 and 28a. The metallicwire 28, which is fusible, is connected to a bracket on the rear portionof a drop-in thermocouple 11 after the thermocouple has been removedfrom the thermocouple assembly and placed on the charging chute l6.Charging chute 16 includes holding portion 29 and a funnellike chargingportion 30. The fusible wire 28 and the second binding post 27 form ameans of restraining the thermocouple from premature entry into thefurnace. The second wire 28a extends rearwardly from the second bindingpost 27 through conduit 21 through the rear wall 19 and is connected inseries with an electrical switch 28c and power source 28d to form anelectrical circuit 28b shown schematically in FIG. 2. When the switch280 is closed, sufficient current flows in the circuit to generate heat,whereby wire 28 melts releasing the thermocouple 11.

Turning now to FIG. 3, the holding portion 29 of the inclined chute 16has two sides 15a which converge to form the funnellike charging portion30. The holding portion 29 is the same width as the box 15 to make itpossible to place a plurality of drop-in thermocouples in position readyfor charging.

The funnellike charging portion 30 extends vertically downwardly so thata drop-in thermocouple may be guided vertically downwardly into thefurnace.

FIG. 4 shows one of the vertical-parallel ribs 20 which divide the box15 into the compartments. The conduit 21 is attached to the vertical rib20 and extends the length thereof. The wire 28a connecting the fusiblewire 28 electrical switch and power source to form the aforementionedelectrical circuit is supported inside the conduit 28a. The gas passage26 formed by the legs 20a and 20b of the vertical rib 20 and a portionof the base 17 of the box 15 allows a coolant gas to be passed forwardlyto the inclined chute l6 and the forward portion of the box 15.

FIG. 5 shows another embodiment of the apparatus of the inventionmounted in a vertical position. It is preferred that in this embodimentthe compartmentalized box 15 be generally square in cross section. Inthis embodiment, the base 17 and the cover 18 of the horizontal box 15now become two fixed opposite parallel sidewalls and the rear wall 19 ismade removable to allow positioning of the thermocouple assembliestherein. The bracket 23, first binding posts 24, anchor post 22 and gasintake 25 will be mounted on the rear wall at the rear or upper portionof the compartmentalized holding box 15. The second binding post 27 willalso be mounted on the rear wall of the box 15. The fusible wire 28 willextend from the bracket on the rear portion of the thermocouple 11 tothe second binding post 27 and the wire 28:: will extend outwardlythrough the rear wall of the box 15. The charging chute consists of aholding portion 29 and a charging portion 30. The drop-in thermocoupleswill hang freely in the holding portion 29 of the chute 16 in thisembodiment. When released, the thermocouples will fall through a hole14' cut in the exhaust hood 14b into the furnace.

In the use of the apparatus to introduce a drop-in thermocouple into amolten ferrous bath in a basic oxygen furnace to obtain the temperaturethereof, a plurality of drop-in thermocouple assemblies are placed incompartments in the holding box. The assemblies are opened and thedrop-in thermocouples are placed in the holding portion of the chute.The fusible wire is attached to the bracket of each of the drop-inthermocouples. The wire restrains the thermocouples from prematurecharging into the furnace. The wire forms one element of an electricalcircuit which remains open until a temperature measurement is required.Portions of the thermocouple cables are removed from the rear portion ofthe assemblies and several turns of each cable are taken around theanchor post to prevent the cable from being pulled into the furnace whenthe drop-in thermocouple is charged into the furnace. The free ends ofthe wires in the cable extend through the rear wall of the box and areattached to a binding post to which electrical leads from the recordingdevice have been fastened. After the thermocouples have been preparedfor charging, the box is closed and a coolant, for example, air underlow pressure is introduced into the box to cool the contents thereof andto prevent ingress of dust and flame.

When a temperature measurement is required, the electrical circuit ofwhich the fusible restraining metallic wire is an element, is closed bythe furnace operator at his console. The current which flows in thecircuit is sufficient to heat the wire to its melting temperature,thereby releasing one of the dropin thermocouples. The thermocoupleslides down the inclined chute and into the furnace. The anchor postprevents the cable from being pulled into the furnace.

Of course, the excessive heat in the furnace burns through the cablewithin a short time. However, the cable resists burning a sufficientlength of time, for example, about 3 seconds to 6 seconds to obtain arecorded temperature measurement.

The positive gas pressure is kept in the apparatus at all times to keepthe inside of the box substantially dust free and at a substantiallyeven temperature. The apparatus of the invention is reliable and reducesthe hazards of obtaining temperature measurements to a minimum.

What we claim is:

1. Apparatus for introducing a drop-in thermocouple into a moltenferrous bath in a basic oxygen furnace comprising:

a. a closed-compartmentized holding box having a forward portion and arear portion, sidewalls, a cover, a base, a rear wall and a plurality ofinterior ribs,

b. a first binding means extending outwardly from said rear wall of saidbox,

c. anchor means extending vertically upwardly from said base in saidrear portion of said box,

d. gas entry means in said base in said rear portion of said box,whereby a cooling gas may be introduced into said box to regulate thetemperature of the contents therein and to prevent ingress of dust, dirtand flame into said box,

e. restraining means in said forward portion of said box,

f. a closed inclined chute extending forwardly and downwardly from saidfront portion of said box, and

g. means for releasing said restraining means to permit a thermocoupleto drop into the furnace.

2. Apparatus as claimed in claim 1 in which the restraining means ofsubparagraph (e) includes a metallic fusible wire having one endattached to said thermocouple.

3. Apparatus as claimed in claim 1, in which the means for releasingsaid restraining means in subparagraph (g) includes an electric circuitformed in part by said metallic fusible wire whereby closing saidelectric circuit causes said wire to melt and release said thermocouple.

2. Apparatus as claimed in claim 1 in which the restraining means ofsubparagraph (e) includes a metallic fusible wire having one endattached to said thermocouple.
 3. Apparatus as claimed in claim 2, inwhich the means for releasing said restraining means in subparagraph (g)includes an electric circuit formed in part by said metallic fusiblewire whereby closing said electric circuit causes said wire to melt andrelease said thermocouple.